How double glazed windows can improve your home’s energy efficiency

Keeping your house warm in winter and cool in summer is everyone’s ideal situation however this can lead to higher energy bills from using your heater and air conditioning more frequently.

In combination with your heating the type of glass and frames used in your home’s windows also has an impact on thermal performance. Through windows, around 40% of your home’s heating energy can be lost due to conduction and 87% of its heat gained from direct sunlight.

Double glazed windows are an energy efficient insulation option for your home as they can reduce the need to use heating and cooling appliances that rely on electricity. We’ve compiled the information below to provide the basics of double-glazed windows. If you are looking to install double glazed windows at home, it’s important to conduct your own research and discuss your needs with a certified double-glazed windows provider.


What’s the difference between single and double glazed windows?

Double glazed windows are windows with two glass panes. There is a gap between each glass pane that is airtight, sealed and filled with argon gas which acts as a barrier between the air inside and outside of the house. 


Single glazed windows only have one glass pane, which minimises its insulation capabilities as the single glass pane is the only barrier between the temperature outside and inside your home.

Double glazed window frames are made from uPVC (unplasticised polyvinyl chloride) which is more airtight than aluminium frames commonly used on single glazed windows. Frames can also be made from timber and aluminium.



What are the benefits of double glazed windows?

Insulation and temperature control

The combination of two glass panels and the argon gas provides more than double the barrier between the air inside and out, providing more insulation and reducing the heat lost or gained when compared to a traditional single glazed window.

Improved energy efficiency and reduced electricity bills

The climate zone of where you live will influence how much you use heaters, fans, and air conditioning. 20%-50% of energy consumption in homes can be attributed to using devices that keep your house warm and/or cool.

Installing double glazed windows can result in up to a 30% reduction of heat loss in the home minimising the need to use appliances that rely on electricity to keep your house warm. This can subsequently result in a lower energy bill as the energy efficiency of double glazed windows reduces the need to use appliances.

Sound proofing

The two glass panes and gap filled with argon gas in double glazed windows are also a good barrier to outside noise entering your home. The tightly sealed window frame also makes it harder for noise to seep through cracks.


The double frames coupled with the glazing add an additional layer of security making it harder for thieves to break into your home. The windowpane and mechanisms (e.g. lock and handle) are also stronger than windows frames made from wood making them harder to tamper with and more secure.


What are the disadvantages of double glazed windows?


They are more expensive than single glazed windows. Look at your energy bill to determine your operating expenses on heaters, air conditioning or other climate control appliances to see if its cost effective to install. They are also expensive to replace.

Maintenance and repair

Double glazed windows require the same cleaning as a single pane window. Be mindful of the area between the two windowpanes, it should not need cleaning as the area is airtight so no dirt should enter. Watch out for cracks too, if not treated immediately they may turn into a larger crack and potentially shatter. Cracks can also minimise the energy efficiency of the windows.

Over time the window may need resealing and the efficiency of the glazing will wane. To determine if the seal needs to be replaced monitor the area around the window for any water leakages. If you feel a draught when the window is closed it could also mean the sealing needs to be replaced. 

If the glazing on the windows wears down over time you may need to replace the window or have them reglazed.

Managing condensation

Condensation on single pane windows is easy to wipe down. If it appears in the middle of the two panes in double glazed windows it can be harder to manage. High humidity inside your home can create condensation. Also monitor the window for cracks as cold air entering cracks could result in condensation.


What do I need to consider before installing?


Double glazed windows are usually priced by the square metre and there are a few variables that influence their cost:

  • The number of double glazed windows you want to install
  • The windows size and thickness
  • Installation fees
  • Window style
  • Handles and locks
  • Custom made
  • Retrofitted (adding an extra glass panel to an existing window)

You may be restricted on design due to the uPVC used to make the frames. This could be an issue if you live in a heritage home or location where you are required to follow strict design rules.


Double glazed windows and their frames are heavier than single pane ones so the area around the window will need to be sound to support it. Before you install them, discuss with your provider if weight could be an issue.


More information

The information we’ve provided above is general and should be used as a starting point in your research. Discuss your needs and any questions with a certified provider. If you’d like to learn more about glazing and double glazed windows, see the useful articles listed below:


You may be eligible for a Green Home Loan

By making your home more energy efficient and reducing its impact on the environment you may qualify for a discounted Green Home Loan. Find out more about our Green Home Loans here.